High-temperature applications – review and outlook

What was the project about?
Based on the need for development in the field of additive manufacturing of gas turbine components, a consortium of 9 partners was formed, who together wanted to leave behind the state of the art. From 2020 to 2022, the small and medium-sized companies CellCore, Friendship Systems, Contact Software and Optris from Berlin and Brandenburg worked together with the users Siemens & Siemens Energy and the research institutes TU Berlin, Fraunhofer IPK and the Federal Institute for Materials Research and Testing BAM.
The goals were, among others, the improvement of design approaches – and tools, an extended process understanding in the field of selective laser beam melting (PBF-LB/M), the prediction of creep properties, the evaluation of the influence of operating media or conditions on the change of properties, digital images of the process chain and much more.

What results have been achieved?
The work in the HTA project is divided into 3 strands, which are also used here to structure and summarize the results.

Additive manufacturing:

• Improvement of the industrial product development process through intensive cooperation between TU Berlin and Siemens Energy.
• Extension of the software Siemens NX with a plug-in of the company Friendship Systems for distortion reduction of PBF-LB/M components
• Design and evaluation of new cooling concepts, which could only be realized by the degrees of freedom of additive manufacturing
• Concept development for large multi-laser systems and high-temperature laser powder bed systems
• Analysis and pre-development of acoustic defect detection during the build process as well as evaluation of OEM-independent camera systems for quality assurance
• The collaboration led to the further development of gas turbine combustor components

New Materials:

• Powder characterization workflow elaborated and powder aging analysis of artificially aged nickel-based superalloys.
• Systematic analysis of interactions in the field “process parameters – geometry – position in the build space – plant” for the material Haynes 282
• Experimental development of an optimized heat treatment for two nickel-base superalloys
• Setup of microstructure simulation (PBF-LB/M) and derivation of volume elements as input for the calculation of creep properties
• Oxidation and nitriding tests of additive and conventional specimens showed boundary layer changes and allowed evaluation of exposed microstructure
• Construction of guide vane prototypes from the alloy IN738LC

Figure 2 Multi-scale model development

Digitization:

• Structure of the ontology
• Development of the digital twin
• Further development of CONTACT Software’s IoT platform (demo data from HTA and additional applications integrated)

Figure 3 Overview of an idealized digitized process chain for additive manufacturing – from the idea to the design process to manufacturing as well as the feedback of the manufacturing data into the design process
What’s next?
Phase II of HTA will start in 2023, with an increased focus on further additive processes (generative assembly with metal wire “WAAM” and selective electron beam melting). The process of the first phase “selective laser beam melting” will become part of the topics post-processing and sustainable product creation. This will enable new research foci to be formed in order to increase the level of technology maturity and to further optimize the established laser beam melting process in terms of the process chain (post-processing). In addition, life cycle assessment will be considered and recycling of powder and support structures will be investigated to maximize resource efficiency.
Proven partners from the 1st phase and new partners, mainly SMEs, have joined, so that a certain consistency is also ensured in the cooperation and the new partners bring fresh wind and new topics into the project, in order to further develop Berlin as a 3D printing location together with the major companies Siemens and Siemens Energy. In addition, the BTU Cottbus is on board as a partner from Brandenburg and will support primarily with process know-how in the area of additive manufacturing/WAAM.

Both project phases are funded by Investitionsbank Berlin (IBB), co-financed by the European Regional Development Fund (EFRE).